WASHINGTON — President Donald Trump tamped down expectations that he is close to declaring a national emergency to get the money he desires to build his long-promised U.S.-Mexico border wall as a three-week impasse closing parts of the government continued on Friday.

Meanwhile, some 800,000 federal employees, more than half still on the job, missed their first paycheck under a stoppage that tied a record for the longest government shutdown. With the closure's growing impact on the economy, national parks and food inspections, some Republicans are becoming uncomfortable with Trump's demands.

Lawmakers tried to reassure federal employees that Congress was aware of the financial hardship they are enduring. By a vote of 411-7, the House passed a bill requiring that all government workers receive retroactive pay after the partial shutdown ends. The Senate approved the bill unanimously Thursday. The president is expected to sign the legislation.

Trump visited McAllen, Texas, and the Rio Grande on Thursday to highlight what he calls a crisis of drugs and crime along the border. He suggested that if he cannot reach an agreement with House Democrats on funding the border wall, he would declare a national emergency.

But speaking to state and local leaders Friday, Trump said he wasn't ready to do that just yet. He said lawmakers can also take that step, even though there's no indication they would.

The "easy solution is for me to call a national emergency ... but I'm not going to do it so fast," Trump said.

Bypassing Congress' constitutional control of the nation's purse strings would lead to certain legal challenges and bipartisan charges of executive overreach. Trump said his lawyers had told him the action would withstand legal scrutiny "100 percent."

The wall was the central promise of Trump's winning campaign in 2016. Supporters have tried to convince him that an emergency declaration is the best option to end the shutdown and would give him political cover to reopen the government without appearing to be caving on his pledge.

But not everyone in the administration is on board.

Senior aide Jared Kushner, who traveled with the president to Texas, is among those urging caution on the declaration, according to a person familiar with Kushner's thinking but not authorized to publicly discuss the issue.

Trump is growing more frustrated as the shutdown drags on and is complaining that his aides are not offering him an exit strategy.

In the meantime, the administration has taken steps to lay the groundwork should Trump issue the declaration.

The White House has directed the Army Corps of Engineers to comb through its budget in search of money for the wall, including looking at $13.9 billion in unspent disaster relief funds earmarked for areas including hurricane-damaged Puerto Rico, Texas and more than a dozen other states. That's according to a congressional aide and administration official familiar with the matter who spoke on condition of anonymity because they were not authorized to speak publicly about the request.

Rep. Mark Meadows, R-N.C., a lawmaker with a close relationship with the president, discounted that option, saying it was not "under very serious consideration."

Defense Department officials had already been poring over data on more than $10 billion in military construction projects to determine how much of it would be available for emergency spending this year.

On Friday, officials in Puerto Rico said diverting disaster money to the wall was "unacceptable" and that the island was struggling to recover from Hurricane Maria, the Category 4 storm that hit more than a year ago and caused more than $100 billion in damage

Gov. Ricardo Rossello said the wall should not be funded "on the pain and suffering" of U.S. citizens who have faced tragedy after a natural disaster.

It was not clear what a potential compromise between the White House and Congress might entail. Efforts at negotiating a broader immigration deal involving immigrants brought to the country illegally as children collapsed with little progress.

Sen. Lindsey Graham, R-S.C., said at one point that he didn't "see a path in Congress" to end the shutdown, then stated later that enough was enough: "It is time for President Trump to use emergency powers to fund the construction of a border wall/barrier."

Vice President Mike Pence visited the Washington headquarters for U.S. Customs and Border Protection and pledged that the administration will keep fighting for the border wall.

"Just as you fight every day to keep our nation safe, this president and this administration will keep fighting to build the wall and give you the resources and reforms you need to do your job," Pence told several dozen unformed agents. "That's my promise."

The partial shutdown would set a record early Saturday, stretching beyond the 21-day closure that ended Jan 6, 1996, during President Bill Clinton's administration.